# just wanted to do a couple dyno pulls (JR TUNE INSIDE) **URL:** \ **Category:** Shift518 Automotive\ **Created:** [August 31, 2010, 4:43pm UTC](https://forums.speedlife.net/t/just-wanted-to-do-a-couple-dyno-pulls-jr-tune-inside/254252 "2010-08-31T16:43:42Z")\ **Posts on this page:** 1\ **Showing post:** 35
**Author:** ![Alpine](https://avatars.discourse-cdn.com/v4/letter/a/4da419/32.png) [@Alpine](https://forums.speedlife.net/u/Alpine)\ **Post date:** [September 1, 2010, 1:43pm UTC](https://forums.speedlife.net/t/just-wanted-to-do-a-couple-dyno-pulls-jr-tune-inside/254252/35 "2010-09-01T13:43:44Z")
> [@Looking for pocket bike Racers](https://forums.speedlife.net/t/looking-for-pocket-bike-racers/34742/3): > > what do u mean how does it work? it works beastly and blows hp-tuners outta the WATER :rofl Again, like I said on the last page, it’s obviously dependent on platform. With MY car and my own personal EXPERIENCE over the last 3 years of owning it and tuning it, I’ve found out that the factory MAF/ecu is not sensitive enough to pick up on changes in air density. SO, in the WINTER, when it’s COLDER, it needs to be re-calibrated. Also, the LSJ motor has a non-return style fuel system, so the #4 cylinder bank (furthest away on the rail) runs especially lean when the temperature changes and melts pistons and other fun things of that nature. --- _[View the full topic](https://forums.speedlife.net/t/just-wanted-to-do-a-couple-dyno-pulls-jr-tune-inside/254252)._